1. Field of the Invention
The present invention relates to a retainer for use in a roller bearing.
2. Description of the Related Art
As shown in FIG. 16A, a retainer 90 includes a comb-like annular body 95, a ring-like cover 94, and a rivet 96 connecting the comb-like annular body 95 to the ring-like cover 94. The retainer 90 is an annular body having a pair of annular portions 92, 94 provided on the axial sides of a pocket 91 and a plurality of columns 93 connecting the pair of annular portions 92, 94 provided on the circumferential sides of the pocket 91. In other words, the rectangular pocket 91 is defined by the annular portions 92 and 94 and the column 93.
The pocket 91 of the retainer 90 has four corners. The comb-like annular body 95 has corners formed in an arc having a radius Rc of curvature. The radius Rc of curvature is predetermined to be smaller than the length of the chamfer of the end of a roller (not shown) to avoid an interference with the roller received in the pocket 91.
FIG. 16B is a sectional view taken on the line B-B of FIG. 16A illustrating a section of the column 93.
An important problem for the enhancement of the strength of the retainer 90 is how the strength of the corners of the pocket 91 onto which stress is concentrated is enhanced.
In order to relax the concentration of stress onto the corners of the pocket 91, it is proposed that the radius Rc of curvature of the corners of the pocket 91 be raised. However, this causes interference of the corners with the chamfer of the end of the roller, Thus, the radius Rc of curvature cannot be raised too much, occasionally making the relaxation effect insufficient.
The invention has been worked out under these circumstances. An aim of the invention is to provide a retainer for roller bearing having a drastically enhancement of the strength of the corners of the pocket and hence the retainer can be attained by a simple structure.
The foregoing aim of the invention is accomplished by the following constitution of retainer.
A retainer for roller bearing comprising a pair of annular portions, a plurality of columns provided between the annular portions and a plurality of pockets defined by the annular portion and the column each for receiving a roller, wherein an indented relief is provided on the corners of the plurality of pockets and the circumferential average width d (mm) of the column at the area where the indented relief is provided, the axial thickness t (mm) of the annular portion at the area where the indented relief is provided, the radius r (mm) of curvature of the indented relief, the average diameter Da (mm) of the roller and the pitch circle diameter dm (mm) of the roller bearing satisfy the following relationship [1]:
0.07xc3x97dm+20xe2x89xa6(2/d+4/t+1/r)xc3x97Daxe2x89xa60.07xc3x97dm+50xe2x80x83xe2x80x83[1]
In accordance with the foregoing retainer for roller bearing, the indented relief 15 having a predetermined size provided on the corners of the pocket 11 make it possible to remarkably relax the concentration of stress onto the corners of the pocket of the retainer (e.g., retainer for cylindrical roller bearing) 10 as shown in FIG. 1. Thus, the strength of the retainer 10 can be drastically enhanced.
Further, as shown in FIG. 2, the indented relief 15 provided on the corners of the pocket 11 form a passage communicating the space on the outer ring side (space between the retainer 10 and the outer ring (not shown)) to the space on the inner ring side (space between the retainer 10 and the inner ring 18). The lubricant attached to the surface of the rollers 19 is partly scratched off by the column 13 of the retainer 10 but is not scratched off the column 13 at the indented relieves 15 so that it moves, e.g., from the space on the outer ring side to the space on the inner ring side. Since the indented relief 15 is disposed very close to the position at which the rib 18a provided on the inner ring 18 or the like and the end face of the roller 19 come in contact with each other, the lubricant is sufficiently supplied into the contact position 18b. In this arrangement, troubles such as seizing and abrasion on the contact position 18b can be prevented, making it possible to improve the bearing performance.